SSH: move knownhost logic to separate function

This commit is contained in:
Daniel Stenberg 2011-04-20 22:43:41 +02:00
parent b903186fa0
commit 9869668884
1 changed files with 126 additions and 112 deletions

192
lib/ssh.c
View File

@ -504,100 +504,16 @@ static int sshkeycallback(CURL *easy,
#define libssh2_session_startup(x,y) libssh2_session_handshake(x,y)
#endif
/*
* ssh_statemach_act() runs the SSH state machine as far as it can without
* blocking and without reaching the end. The data the pointer 'block' points
* to will be set to TRUE if the libssh2 function returns LIBSSH2_ERROR_EAGAIN
* meaning it wants to be called again when the socket is ready
*/
static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block)
static CURLcode ssh_knownhost(struct connectdata *conn)
{
CURLcode result = CURLE_OK;
struct SessionHandle *data = conn->data;
struct SSHPROTO *sftp_scp = data->state.proto.ssh;
struct ssh_conn *sshc = &conn->proto.sshc;
curl_socket_t sock = conn->sock[FIRSTSOCKET];
#ifdef CURL_LIBSSH2_DEBUG
const char *fingerprint;
#endif /* CURL_LIBSSH2_DEBUG */
const char *host_public_key_md5;
int rc = LIBSSH2_ERROR_NONE, i;
int err;
int seekerr = CURL_SEEKFUNC_OK;
*block = 0; /* we're not blocking by default */
do {
switch(sshc->state) {
case SSH_S_STARTUP:
sshc->secondCreateDirs = 0;
sshc->nextstate = SSH_NO_STATE;
sshc->actualcode = CURLE_OK;
rc = libssh2_session_startup(sshc->ssh_session, sock);
if(rc == LIBSSH2_ERROR_EAGAIN) {
break;
}
else if(rc) {
failf(data, "Failure establishing ssh session");
state(conn, SSH_SESSION_FREE);
sshc->actualcode = CURLE_FAILED_INIT;
break;
}
/* Set libssh2 to non-blocking, since everything internally is
non-blocking */
libssh2_session_set_blocking(sshc->ssh_session, 0);
state(conn, SSH_HOSTKEY);
/* fall-through */
case SSH_HOSTKEY:
#ifdef CURL_LIBSSH2_DEBUG
/*
* Before we authenticate we should check the hostkey's fingerprint
* against our known hosts. How that is handled (reading from file,
* whatever) is up to us. As for know not much is implemented, besides
* showing how to get the fingerprint.
*/
fingerprint = libssh2_hostkey_hash(sshc->ssh_session,
LIBSSH2_HOSTKEY_HASH_MD5);
/* The fingerprint points to static storage (!), don't free() it. */
infof(data, "Fingerprint: ");
for(rc = 0; rc < 16; rc++)
infof(data, "%02X ", (unsigned char) fingerprint[rc]);
infof(data, "\n");
#endif /* CURL_LIBSSH2_DEBUG */
/* Before we authenticate we check the hostkey's MD5 fingerprint
* against a known fingerprint, if available. This implementation pulls
* it from the curl option.
*/
if(data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5] &&
strlen(data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5]) == 32) {
char buf[33];
host_public_key_md5 = libssh2_hostkey_hash(sshc->ssh_session,
LIBSSH2_HOSTKEY_HASH_MD5);
for(i = 0; i < 16; i++)
snprintf(&buf[i*2], 3, "%02x",
(unsigned char) host_public_key_md5[i]);
if(!strequal(buf, data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5])) {
failf(data,
"Denied establishing ssh session: mismatch md5 fingerprint. "
"Remote %s is not equal to %s",
buf, data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5]);
state(conn, SSH_SESSION_FREE);
sshc->actualcode = CURLE_PEER_FAILED_VERIFICATION;
break;
}
}
CURLcode result = CURLE_OK;
#ifdef HAVE_LIBSSH2_KNOWNHOST_API
if(data->set.str[STRING_SSH_KNOWNHOSTS]) {
/* we're asked to verify the host against a file */
struct ssh_conn *sshc = &conn->proto.sshc;
int rc;
int keytype;
size_t keylen;
const char *remotekey = libssh2_session_hostkey(sshc->ssh_session,
@ -704,8 +620,106 @@ static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block)
break;
}
}
#endif /* HAVE_LIBSSH2_KNOWNHOST_API */
#else /* HAVE_LIBSSH2_KNOWNHOST_API */
(void)conn;
#endif
return result;
}
/*
* ssh_statemach_act() runs the SSH state machine as far as it can without
* blocking and without reaching the end. The data the pointer 'block' points
* to will be set to TRUE if the libssh2 function returns LIBSSH2_ERROR_EAGAIN
* meaning it wants to be called again when the socket is ready
*/
static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block)
{
CURLcode result = CURLE_OK;
struct SessionHandle *data = conn->data;
struct SSHPROTO *sftp_scp = data->state.proto.ssh;
struct ssh_conn *sshc = &conn->proto.sshc;
curl_socket_t sock = conn->sock[FIRSTSOCKET];
#ifdef CURL_LIBSSH2_DEBUG
const char *fingerprint;
#endif /* CURL_LIBSSH2_DEBUG */
const char *host_public_key_md5;
int rc = LIBSSH2_ERROR_NONE, i;
int err;
int seekerr = CURL_SEEKFUNC_OK;
*block = 0; /* we're not blocking by default */
do {
switch(sshc->state) {
case SSH_S_STARTUP:
sshc->secondCreateDirs = 0;
sshc->nextstate = SSH_NO_STATE;
sshc->actualcode = CURLE_OK;
rc = libssh2_session_startup(sshc->ssh_session, sock);
if(rc == LIBSSH2_ERROR_EAGAIN) {
break;
}
else if(rc) {
failf(data, "Failure establishing ssh session");
state(conn, SSH_SESSION_FREE);
sshc->actualcode = CURLE_FAILED_INIT;
break;
}
/* Set libssh2 to non-blocking, since everything internally is
non-blocking */
libssh2_session_set_blocking(sshc->ssh_session, 0);
state(conn, SSH_HOSTKEY);
/* fall-through */
case SSH_HOSTKEY:
#ifdef CURL_LIBSSH2_DEBUG
/*
* Before we authenticate we should check the hostkey's fingerprint
* against our known hosts. How that is handled (reading from file,
* whatever) is up to us. As for know not much is implemented, besides
* showing how to get the fingerprint.
*/
fingerprint = libssh2_hostkey_hash(sshc->ssh_session,
LIBSSH2_HOSTKEY_HASH_MD5);
/* The fingerprint points to static storage (!), don't free() it. */
infof(data, "Fingerprint: ");
for(rc = 0; rc < 16; rc++)
infof(data, "%02X ", (unsigned char) fingerprint[rc]);
infof(data, "\n");
#endif /* CURL_LIBSSH2_DEBUG */
/* Before we authenticate we check the hostkey's MD5 fingerprint
* against a known fingerprint, if available. This implementation pulls
* it from the curl option.
*/
if(data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5] &&
strlen(data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5]) == 32) {
char buf[33];
host_public_key_md5 = libssh2_hostkey_hash(sshc->ssh_session,
LIBSSH2_HOSTKEY_HASH_MD5);
for(i = 0; i < 16; i++)
snprintf(&buf[i*2], 3, "%02x",
(unsigned char) host_public_key_md5[i]);
if(!strequal(buf, data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5])) {
failf(data,
"Denied establishing ssh session: mismatch md5 fingerprint. "
"Remote %s is not equal to %s",
buf, data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5]);
state(conn, SSH_SESSION_FREE);
sshc->actualcode = CURLE_PEER_FAILED_VERIFICATION;
break;
}
}
result = ssh_knownhost(conn);
if(!result)
state(conn, SSH_AUTHLIST);
break;